Otosclerosis is a bony dyscrasia of the capsule of the bone around the inner ear. The first sign of otosclerosis is a small growth of spongy bone tissue around the inner ear. This softened bone interferes with the way the inner ear works, producing a broad range of unfavorable symptoms such as mechanical hearing loss, inner ear or sensorineural hearing loss, dizziness, tinnitus, and Meniere's syndrome. Mechanical hearing loss occurs when this overgrown soft bone interferes with the vibration of the last bone next to the inner ear, and can go on to a total hearing loss.
The diagnosis for otosclerosis remains difficult to make. It often requires special x-rays of the inner ears; thorough knowledge of the anatomy and pathology of the ear, especially as related to otosclerosis; patient clinical information including history, physical examination; and results of patient hearing and auditory tests.
Treatment for otosclerosis is equally difficult. There is no known medicine available for treating otosclerosis. In the 1960's the only treatment for this disorder was to supplement the diet with sodium fluoride. In 1969, patients were placed on sodium fluoride and calcium carbonate. However, only some patients receiving these treatments experienced an improvement in symptoms. A hearing aid may be worn; however, natural hearing is preferred, if possible. Currently, surgery (e.g., a stapedectomy) has been found to be the most effective method of managing the mechanical hearing loss of otosclerosis. A stapedectomy is removal of the stapes bone. However, a stapedectomy is not 100% effective, and there are risks and complications of the procedure. In some instances, surgery can worsen the hearing loss or result in no improvement in hearing or no change in tinnitus. Potential side effects of a stapedectomy include a change in sense of taste on the same side of the tongue, vertigo, perforation of the tympanic membrane, and intolerance of very loud noises. In addition, treatment of the symptoms of otosclerosis has involved dietary modifications, such as a diet of low salt, low sugar, and low in saturated fats.
In 1997, it was found that bisphosphonates could be useful in the treatment of otosclerosis. Bisphosphonates have been approved by the FDA for use in the treatment of Paget's disease of bone and for osteoporosis. Conventional dosage amounts, e.g., those approved by the FDA, or those recommended in scientific literature, result in some benefit for otosclerosis patients, although the effect could be limited and in some cases transient.
Thus, there exists a need in the art to treat the sensorineural hearing loss, dizziness, tinnitus, and Meniere's disease that occurs with otosclerosis, and a need to adapt new dosage therapies for treating otosclerosis, eliminating or delaying the need for surgical intervention and/or dietary modifications.